Hybrid seeds--tomatoes are a good example--offer resistance to various
plant diseases. We give that up when we use non-hybrid seeds. There are
viable offsets: plant more seeds and let disease and the bugs and birds get
a larger share but you still get what you want. Keep planting your own
seeds and select each year those fruits that did the best, then save seeds
from them. And the biggie: learn how to garden better, growing plants that
are so damn strong that they resist well normal onslaughts.